1. Field of the Invention
The present invention relates to a soil compacting device including a soil contact element that is driven to oscillate linearly by a movement conversion device. Such soil compacting devices are known and are also referred to as tampers or vibrating tampers.
2. Discussion of the Related Art
In such tampers, it is known to use either an internal combustion engine, for example a gasoline or diesel engine, or an electric drive mechanism. Internal combustion engines have the advantage that they are independent of external energy sources. However, internal combustion engines have the disadvantage of emission of exhaust gases and noise. The problem of noise or pollutant emission does not exist in the case of electric drive mechanisms. However, for these mechanisms it is necessary to provide a power network or a generator in order to enable operation of the electric motor. In addition, a mains cable is required in order to enable the tamper to be connected to the power source (mains connection). This impairs the ease of handling of electric tampers.
FIG. 1 shows a schematic side view of a known tamper.
In the upper area, an internal combustion engine 1 is situated between a guide bar 2. Internal combustion engine 1 receives fuel from a tank 3 that is attached to guide bar 2. Using guide bar 2, an operator can guide the tamper in a known manner. Underneath internal combustion engine 1, a housing 4 is provided in which there is situated a movement conversion device for converting a rotational movement of internal combustion engine 1 into an oscillating linear movement of a soil contact element 6. Movement conversion device 5 is explained in more detail below on the basis of FIG. 2. Soil contact element 6 is fashioned as a tamper foot.
FIG. 2 shows a section through housing 4.
From internal combustion engine 1, an engine shaft 7 extends vertically downward. A centrifugal clutch 8, which forms a clutch device, is placed on the conical end of engine shaft 7. Centrifugal clutch 8 is fashioned in a known manner and has a plurality of centrifugal force elements 9 that are held in a radially internal initial position by springs 10. As soon as the rotational speed of engine shaft 7 exceeds a prespecified value, centrifugal force elements 9 move outward against the action of springs 10, and thus form a positive or frictional connection between an internally situated drive bank 11 of the centrifugal clutch and an externally situated driven bank 12. Driven bank 12 is formed by a clutch bell 13.
Clutch bell 13 is part of an intermediate shaft 14 whose rotational movement is transmitted to a crank disk 15 via a bevel gear tooth system.
On crank disk 15, there is provided a crank pin 16 that drives a connecting rod 17 in a known manner. Connecting rod 17 is coupled to soil contact element 6 via an intermediate piston and spring assemblies (not shown). In this way, the movement of connecting rod 17 can be converted into the oscillating linear movement of soil contact element 6.
The design of such a tamper, and in particular of movement conversion device 5, is known and therefore need not be explained in more detail here.